The invention relates to a method and an apparatus for determining the position and/or the configuration of an object under observation.
Conventional methods for determining the configuration of an object use a coaxial method in which a laser light beam is impinged on the object, and a reflected light is detected by the camera and a position and a configuration of the object are determined.
FIG. 10 illustrates the principle of the conventional coaxial method. As shown in the figure, a laser light beam 5 is impinged on an object 2 and is reflected to a light receiving portion of a detector 3 (camera). From the known positions and angles of the laser source 1 and camera 3, a position and a configuration of the object are calculated.
Although the method is suitable for a very accurate measurement, a detector 3 must be set so that its optical axis is coaxial or coincident with the direction of the propagating wave, which is often difficult and is applicable only to those objects having special shapes and materials.
If the object does not reflect the incident light at all, it is difficult to measure the surface of the object since there is no reflected light. And in the case of a complex surface of the object, it is often difficult to measure the surface of the object for the reason that cameras can not be set in the direction of the reflected light.
further difficulty exists in the optical methods, mainly due to the fact that they do resort to information concerning the conditions of the surface of an object and that they neglect all the information concerning the light beam itself.